2023.09.19 Today's Challenge

https://leetcode.com/problems/find-the-duplicate-number/

LeetCode - The World's Leading Online Programming Learning Platform

문제의 조건으로는 리스트를 변형하지 말라고 했으나, 그냥 간단하게 구현함.

class Solution:
    def findDuplicate(self, nums: List[int]) -> int:
        nums.sort()
        before = -1
        for num in nums:
            if before == num:
                return num
            before = num
        return -1